ci: try fixing multi-platform build

.github/workflows/build-docker-images.yml

@@ -6,7 +6,7 @@ on:
 
 env:
   REGISTRY: ghcr.io
-  IMAGE_NAME: "ghcr.io/silitics/rugpi-bakery:latest"
+  IMAGE_NAME: "ghcr.io/silitics/rugpi-bakery"
   PI_BASE_IMAGE: "https://downloads.raspberrypi.org/raspios_lite_arm64/images/raspios_lite_arm64-2023-05-03/2023-05-03-raspios-bullseye-arm64-lite.img.xz"
 
 jobs:
@@ -19,9 +19,15 @@ jobs:
     steps:
       - uses: actions/checkout@v3
 
+      - name: Docker Meta
+        id: meta
+        uses: docker/metadata-action@v4
+        with:
+          images: ${{ env.IMAGE_NAME }}
+
       - name: Set up QEMU
         uses: docker/setup-qemu-action@v2
-      
+
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v2
 
@@ -31,22 +37,79 @@ jobs:
           registry: ${{ env.REGISTRY }}
           username: ${{ github.actor }}
           password: ${{ secrets.GITHUB_TOKEN }}
-      
+
       - name: Build and Push Image
+        id: build
         uses: docker/build-push-action@v4
         with:
           context: .
           file: docker/Dockerfile.rugpi-bakery
           platforms: ${{ matrix.platform }}
+          labels: ${{ steps.meta.outputs.labels }}
           push: true
           tags: ${{ env.IMAGE_NAME }}
           cache-from: type=gha
           cache-to: type=gha,mode=max
-
+          outputs: type=image,name=${{ env.IMAGE_NAME }},push-by-digest=true,name-canonical=true,push=true
+
+      - name: Export Digest
+        run: |
+          mkdir -p /tmp/digests
+          digest="${{ steps.build.outputs.digest }}"
+          touch "/tmp/digests/${digest#sha256:}"
+
+      - name: Upload Digest
+        uses: actions/upload-artifact@v3
+        with:
+          name: digests
+          path: /tmp/digests/*
+          if-no-files-found: error
+          retention-days: 1
+
+  merge-docker-images:
+    runs-on: ubuntu-latest
+    name: Merge Docker Images
+    needs:
+      - build-docker-images
+    steps:
+      - name: Download Digests
+        uses: actions/download-artifact@v3
+        with:
+          name: digests
+          path: /tmp/digests
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v2
+
+      - name: Docker Meta
+        id: meta
+        uses: docker/metadata-action@v4
+        with:
+          images: ${{ env.IMAGE_NAME }}
+          tags: |
+            type=raw,value=latest,enable=${{ github.ref == format('refs/heads/{0}', 'main') }}
+
+      - name: Login to Container Registry
+        uses: docker/login-action@v2
+        with:
+          registry: ${{ env.REGISTRY }}
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Create Manifest List and Push
+        working-directory: /tmp/digests
+        run: |
+          docker buildx imagetools create $(jq -cr '.tags | map("-t " + .) | join(" ")' <<< "$DOCKER_METADATA_OUTPUT_JSON") \
+            $(printf '${{ env.IMAGE_NAME }}@sha256:%s ' *)
+      
+      - name: Inspect Image
+        run: |
+          docker buildx imagetools inspect ${{ env.IMAGE_NAME }}:${{ steps.meta.outputs.version }}
+
   build-template-image:
     name: Build Image
     runs-on: ubuntu-latest
-    needs: [build-docker-images]
+    needs: [merge-docker-images]
     steps:
       - uses: actions/checkout@v3
         with:
@@ -55,18 +118,18 @@ jobs:
       - name: List Files
         working-directory: ./template
         run: ls -l
-      
+
       - name: Install QEMU
         run: docker run --privileged --rm tonistiigi/binfmt --install arm64
 
       - name: Extract Image
         working-directory: ./template
         run: ./run-bakery extract ${{ env.PI_BASE_IMAGE }} build/base.tar
-      
+
       - name: Customize System
         working-directory: ./template
         run: ./run-bakery customize build/base.tar build/customized.tar
-      
+
       - name: Bake Image
         working-directory: ./template
         run: ./run-bakery bake build/customized.tar build/customized.img